This invention relates to a gas laser generating device of the longitudinal gas flow type having two glow discharge tubes which are arranged left and right on the same axis, each of which has positive and negative electrodes and is filled with circulating gas such as carbon dioxide (CO.sub.2), nitrogen (N.sub.2), helium (H.sub.e), etc.
When the electrodes of each tube are applied with a d.c. voltage from a common electric power source, the glow discharge tubes begin to discharge so that the gas is excited into population inversion and generate a laser.
The lasing is amplified by reflecting the light between two mirrors which are positioned on the left and right ends of the two glow discharge tubes, after which the light exits through one of the two reflecting mirrors.
Such gas laser generating devices of the longitudinal gas flow type are usually used in order to cut or drill steel plates or similar articles because such gas laser generating devices are capable of generating relatively large output power. However, the conventional gas laser generating device as described above has certain defects.
For example, the two glow discharge tubes start to discharge, the discharge starting times of the tubes are different from each other. Therefore, electrical insulating tubes provided between the left and the right glow discharge tubes are disadvantageously applied with a large voltage of the d.c. power source because the electrodes of the two glow discharge tubes are connected to the same electric power source. For this reason, the electrical insulating tubes of a conventional gas laser generating device have to be relatively large and this undesirably increases the size of the whole laser device.